17-iodoheptadecanoic-acid and Cardiomyopathies

Studies of myocardial metabolism by rapidly catabolized fatty acids like omega-I-123-heptadecanoic acid (IHA) are usually limited to one planar view of require sophisticated equipment, such as bidirectional slant-hole collimators or seven-pinhole collimators for multiplane or tomographic views. To solve this problem a normal SPECT camera was utilized to acquire sequentially sampled dynamic studies from up to six different views. This was done by a periodically repeated sequence of acquisitions in different projections, which followed one another clockwise. This procedure overcomes the single-plane limitations of the usual IHA dynamic studies. It reveals regional myocardial patterns of tracer uptake and elimination not obtainable from any single viewing angle. In this way one methodological disadvantage relative to thallium perfusion studies is removed. Furthermore, the non-invasive diagnosis of cardiomyopathies, for which no other radioisotope procedure is appropriate, should be improved using this new method.

Topics: Cardiomyopathies; Fatty Acids; Heart; Humans; Kinetics; Methods; Myocardium; Radioisotopes; Thallium; Tomography, Emission-Computed

In twenty patients with primary congestive cardiomyopathy (COCM) the patterns of accumulation and washout of the fatty acid analogue [17-123I]iodoheptadecanoic acid (I-123 HA) were studied. In contrast to patients with ischemic heart disease, where reduced I-123 HA accumulation was correlated with stenosis of the main coronary arteries, thus usually involving larger wall segments, the patients with COCM concentrated I-123 HA heterogeneously in small spotty segments throughout the entire left-ventricular myocardium. The regional washout half-times varied between 15.1 and 116.2 min. It seems that in patients with severe COCM the elimination half-times are more prolonged than in early stages of the disease. There was no correlation between the regional uptake and the elimination half-times. Sequential myocardial imaging with I-123 HA appears useful for noninvasively diagnosis of COCM.

Topics: Cardiomyopathies; Coronary Disease; Diastole; Fatty Acids; Half-Life; Heart; Heart Septum; Heart Ventricles; Humans; Iodine Radioisotopes; Myocardium; Radionuclide Imaging

To characterize externally detectable changes in the myocardial metabolism of free fatty acids (FFA) and glucose, which are associated with ischemia and cardiomyopathy, omega-123I-heptadecanoic acid (stearic acid analogue), 75Br-phenylpentadecanoic acid, and 3-0-11C-methyl-D-glucose were used as indicators. It could be demonstrated that in the metabolism of free fatty acids at least two different patho-physiological situations may exist. Disturbances in the mechanism of the accumulation of free fatty acids lead to a decrease of the amount of the free fatty acids which are available for energy production (these disturbances can be recognized as indicator accumulation defects). Disturbances associated with the mechanism of free fatty acid catabolism lead to a decrease of the ability of the myocardial cell to utilize the free fatty acids (these disturbances can be recognized as changes in indicator elimination rates). Whereas in ischaemic heart disease, the areas with altered FFA accumulation correlate with the areas of altered FFA-elimination, no correlation was found in the case of cardiomyopathy. The 11C-methylglucose seems to be an excellent indicator for the in-vivo assessment of the function of transport system in the myocardial cell membrane.

Topics: Animals; Carbon Radioisotopes; Cardiomyopathies; Coronary Disease; Fatty Acids; Fatty Acids, Nonesterified; Humans; Iodine Radioisotopes; Methylglucosides; Methylglycosides; Mice; Myocardium; Tomography, Emission-Computed

Topics: Cardiomyopathies; Coronary Disease; Fatty Acids; Heart; Humans; Iodine Radioisotopes; Middle Aged; Myocardium; Radionuclide Imaging